iMac updated to Big Sur 11.2.2 a few days ago. I also downloaded Acrobat Reader around the same time. Now I am unable to open Acrobat DC. I get a message that says unable to verify subscription? This is hugely frustrating and impacting my workload.
Also, please try to reset your host file, operating system hosts files map host names to IP addresses. An incorrectly configured hosts file can affect your computer's ability to connect to Adobe's activation servers. For more information please check the step 2 in the above shared help page.